/in/foo.cc: In function 'void tarjan(int)':
/in/foo.cc:30:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<out[s].size();j++)
              ~^~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:79:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<in[i].size();j++)
               ~^~~~~~~~~~~~~
/in/foo.cc:84:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<out[i].size();j++)
               ~^~~~~~~~~~~~~~
/in/foo.cc:91:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<check.size();j++)
              ~^~~~~~~~~~~~~